Electric switch



T. W. GABBL. BLEGTRIG SWITCH.

2 Sheets-Sheet 1.

(No Model.)

10.556,264. Patented Mar. 10,1896..

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T.W-GABBL ELECTRIC SWITCH. 4 No. 556,264, Patented Mar. 10, 1896.

(No Model.) 2 SheetsQ-Sheet 2.

z -nd UNITED STATES PATENT OFFICE..

THEODORE IV. GABEL, OF LANCASTER, PENNSYLVANIA.

ELECTRlC SWITCH.

SPECIFICATION forming part of Letters Patent No. 556,264, dated March 10, 1896.

Application iile May 13,1895. Serial No. 549,090. (Nb model.)

T @ZZ whom, may concern:

Be it known that I, THEODORE IV. GABEL, a citizen of the United States, residing at Lancaster, in the county of Lancaster and State of Pennsylvania, have invented certain Improvements in Electric Switches, of which'the following is a specification.

This invention relates to improvements in devices designed for making and breaking an electric current and changing the course of the same, and is particularly applicable to that class of dental instruments employed in operating on the teeth of the patient; and the objects of the invention are, first, to cut out the instrumentused on the patient, so that the stoppage of the action of said instrument shall be instantaneous; second, to regulate the strength of the current applied, and,third, to reverse said current.

The invention consists in the construction and combination of the various parts,as hereinafter fully described and then pointed out in the claims.

In the accompanying drawings, which form a part of this specification, Figure l is a top view of a foot-rest containing the mechanism embodying my invention, and Fig. 2 a longitudinal vertical section thereof. Fig. 3 is a horizontal section on broken line 3 3 of Fig. 2, showing a top view of the plate supporting the operating mechanism, and Fig. 4 a similar section on broken line 4t at of Fig. 2, showing a bottom view of said plate. Fig. 5 is a vertical section on broken line 5 5 of Fig. 4; Fig. G, a vertical section on broken line 6 6 of Fig. 3, and Fig. 7 a similar section on broken line 7 7 of Fig. 3.

Similar letters indicate like parts throughout the several views.

For the purposes of this specification the Wires connecting the mechanism herein described with the source of electricity are termed line-wires.

Referring to the details of the drawings, A indicates the tread of a hollow foot-rest, having in the toe thereof a curved slot a and in the heel a straight slot a'.

A indicates a horizontal plate to which is attached the mechanism comprising my invention.

B and B are line-wires, D an insulatingcase located on. plate A and containing a resistance-coil D', and E a horizontally-movable switch-lever pivoted to the bottom of said plate A at e. This lever is formed of spring metal and has a post E on its forward end extending up through plate A and the slot a, and is provided with a head or annular rim e'. The rear end e2 of lever E is adapted to be engaged with any one of a number of binding-posts CZ d d2, dac., disposed concentrically with the pivot of lever E and passing up through plate A'.

F F are switch-bars pivotally connected by a non-conducting plate F2 and pivoted above plate A on binding-posts f f', respectively, their free ends being adapted to engage the binding-posts G G and G2, passing through said plate A. On plate F2 is pivoted a post F3, which extends up through slot a and is adapted to be actuated sidewise by the heel of the foot.

The line-wires pass into the foot-rest above plate A through an opening a2. Line-wire B is then carried down through a perforation b in said plate and, as shown at b', over to the pivot e of lever E. Line-wire B is also carried down through a perforation b2, and, as, shown at b3, over to binding-post f', the pivot yof switch-bar F.

The wires II I'I,connected with the dental instrument, also pass into the foot-rest through opening a2, the wire II being carried down through perforation h, and thence to bindingpost G, as shown at h, and wire H down through perforation h2, and thence to binding-post G', as shown at h3.

Below the bottom of plate A' binding-posts G and G2 are connected by a wire g, andthe upper end of binding-post d is connected with thebottom of binding-post f-the pivot of switch-bar F-by a wire g passing through IOO electric current, until said switch reaches binding-post df. \Vhen end e2 of said lever E is engaged with the lower end of bindingpost d the current passes directly from said post to binding-post f-that is to say, without passing through any portion of resistance-coil D'. If, however, the lever E is turned so as to make connection with binding-post d', the current before reaching binding-post (l must first pass through that portion of the resistance-coil whichis interposed between binding-posts d and (Z'. Hence the strength of the current will be diminished accordingly, and in like manner if the lever E is moved into contact with the bindingpost (I2 the current will have to pass through a greater extent of the resistance-coil and there will be a further diminution of the strength of the current, and so on until lever E makes connection with the binding-post d, whereby the entire extent of the resistance coil is introduced into the circuit and the power of the current is reduced to a minimum, further movement of the lever E into contact with the binding-pest (ZG cutting olf the current and switching the dental instru ment out of the circuit. In like manner the power of the current is gradually increased as the lever E swings from the binding-post df" to the binding-post (l.

No particular construction or arrangement of resistance-coil is shown or described, as the same does not form any part of this in'L vention, and any kind of rheostat through which the strength of the electric current can be regulated may be employed.

Switch-lever E is swung to and fro about its pivot by the side pressure of the toe of the ioot on post E'. Said lever being in contact with binding-post d and the switch-bars F and F' contacting, respectively, with binding-posts G' and G, as shown by broken lines R, the current is through line-wire B b', pivot e and lever E, binding-post d and wire g', binding-post j", switch-bar F, binding-post G' and instrument-wi re 7L II', returning through instrument-wire II h', binding-post G, switchbar F', binding-post f' and line-wire 'b3 3'. To reverse the current, switch-bars F and F' are thrown into contact with binding-posts G and (l2, respectively, as shown by breken lines R. The current is then through linewire B V(1', pivot c and lever E, binding-postal and wire y', binding-postf, lever F, bindingpost G and instrinnent-wire 7L' Il., returning through instrument-wire II' 7L, bindingpost G', wire f/ and binding-post G2, lever F', binding-post f 'and line-wire 113B', but it is often desirable to cutout the operating mechanism, so that the movement ol' the instrument may be stoppedinstantaneously. Beneath plate A', and j ust back of slot a, is located a bracket or bridge M of conducting material, which embraces lever E and has one end thereof electrically connected with line-wire B' outside ol the connection of said linewire with the switch-bars by a branch wire m, passing through a perforation m' in plate A' anda binding-screw fm2. By pressing on head e' of post E' lever E is engaged with bridge M, as illustrated by broken lines at M', 2 and 5. The circuit is then throughline-wire B h', pivot c and the front end of lever It, bridge M, binding-screw m2, wire 'In and linewire B'.

I do not restrict myself to cutting` out the operating-instrument by means oli' the short circuit described, nor by means of any construction of short circuit; neither do I limit myself to the other details of construction herein shown and described, as it is obvious that many changes may be made therein without departing from the scope and principle ol my invention.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination, in an electric switch, of a resistance-coil, a series of contacts, each of said contacts having a different pointI el.' connection with the resistance-coil, a conductor-switch formed ei' a plain levcr-bar, an end of said lever-bar having a terminal adapted to engage each of said contacts, a line-wire connected with the fulcrum of the lever-bar, a pair of pivoted conductor switch bars connected by a non-conducting plate, three contacts located within the path oi' travel of the swinging ends of the connected switclrbars, a second line-wire connected with the pivot of one of the connected switch-bars, a conductor connecting the pivot of the other of said connected switch-bars and one of the terminal contacts of the resistance-coil, a connection between the end contacts of said three contacts, a connection between one of said end contacts and the actuated mechanism, and a connection between the center contactof the three contacts and said actu,A ated mechanism, substantially as and forthe purpose specified.

2. The combination, in an electric switch, of a resistance-coil, a series of contacts, each of said conta-cts having a different point of connection with the resistance-coil, a conductorswitch formed of a plain lever-bar, one end of said bar having a terminal adapted to engage each of said contacts, the other end of said lever-bar being formed of spring 1nate rial and adapted to be depressed, a conductorbridge located beneath said lever-bar in position to be engaged by the spring end of said bar when depressed, a line-wire connected with the fulcrum of the lever-bar, a pair of pivoted conductor switch-bars connected by a non-conducting plate, three contacts located within the path of travel of the swinging ends of the connected switch-bars, a second linewire connected with the pivot of one of the connected switch-bars, a conductor connecting the pivot of the other of said connected switch-bars and one of the terminal contacts of the resistance-coil, a connection between the end contacts of said three contacts, a connection between one of said end contacts and IIC) the actuated mechanism, a connection between the center contact of said three contacts and said actuated mechanism, and a direct connection between said bridge and the line-wire connected with said pivot of one of the connected switch-bars, substantially as and for the purpose specified.

3. The combination, in an electric switch, of a hollow foot-rest having a slot in each end thereof, a switch mechanism located in said foot-rest and comprising a resistance-coil, a series of contacts, each of said contacts having a different point of connection with the resistance-coil, a conductor-switch formed of a plain lever-bar, one end of said lever-bar being adapted to engage each of said contacts, the other end of said lever-bar being formed of spring material and adapted to be depressed, a conductor bridge located beneath said bridge in position to be engaged by the spring end of the lever-bar when depressed, a post on said end of the lever-bar passing up through one of the slots in the 'foot-rest, a pair of pivoted conductor switchbars connected by a non-conducting plate, a

post on said plate extending up through the other slot in the foot-rest, three contacts located within the path of travel of the swinging ends of the connected switch-bars, a connection between the end contacts of said three contacts, and a conductor connecting the pivot of one of said connected switch-bars and one of the terminal contacts of the resistance-coil, with a line-wire attached to the pivot of the other of said connected switchbars, another line-Wire attached to the fulcrum of the lever-bar, a connection between said bridge and the line-wire connected with the pivot of one of said connected switchbars, a connection between one of the end contacts of said three contacts and the actuated mechanism, and a connection between the center contact of said three contacts and the actuated mechanism, all substantially as and for the purpose specified.

THEODORE W. GABEL.

'Witnesses JAcoB HALBAcn, WM. R. GERHART. 

